Method and equipment for narrow ore mining

ABSTRACT

For narrow ore mining, shrinkage stopping is used with working equipment, such as a working platform or mining rig (30), which is suspended in guide sections (38) in the roof of the mining chamber, and from which drilling and charging is carried through, the mining chamber communicating with a raise. In the raise, which follows the inclination of the ore body, a transport lift is used designed for receiving the working platform or mining rig (30) in its lift cage (20). The lift cage (20) comprises a transport guide arranged for suspension of the working platform or the mining rig in the lift cage and connectable to a start guide in the roof of the mining chamber.

The present invention relates to a method and an equipment for using, inconnection with narrow ore mining, shrinkage stoping technique with aworking equipment, such as a working platform or mining rig suspended onguide rail sections in the roof of the mining chamber, from whichworking platform or mining rig drilling and charging is carried through,and which before blasting is moved into a raise leading to the miningchamber.

In several places in the world there are great ore deposits in the formof narrow ore bodies containing high grade ore. Due to the lack ofeconomically acceptable techniqiue these ore deposits have hitherto beentaken care of to a very small extent. The ore bodies referred to herehave, by way of definition, a width of an order of magnitude of 4-5meters at most, and they can have a great extension in the height andlength directions. Furthermore, it has turned out that the planes ofthese thin ore bodies to a very great extent lean 45°-90° with respectto the horizontal, with a concentration to the area 60°-70°.

In the Swedish patent 333,342 a mining method is described, whichnowadays is usually called "mechanized shrinkage stoping", and which isused for broader ore bodies. Mining is carried through by means of amining rig which is suspended on guides in the roof of the rock chamber,and from which drilling and charging is carried through. The guidesbeing successively mounted in the roof of the rock chamber from the rig,continuously continue via a rounded off transition into a raise intowhich the mining rig is driven before blasting. Mining with horizontaldrilling is carried through successively from the raise to the end ofthe rock chamber located at most remote from the raise. After finishedhorizontal mining, mining with vertical or close to vertical drilling isstarted from this end back toward to the raise.

The method just described has the great advantage as compared withconventional shrinkage stoping that the loosened ore need not be used asa platform for mining equipment and personal. Thereby the economicalgain is considerably increased since removal of the ore is not dependentfrom the ore excavation.

The object of the present invention is to provide a method andequipment, by means of which mining of narrow ores becomes technicallyand economically practicable.

The invention is based upon the realization that the followingprinciples shall be followed in order to attain this object:

1. The work shall be carried through from main levels, i.e. the narrowore body shall not, as higherto, be reached via an intermediate driftsystem, the installation of which requires considerable amount ininvestment.

2. The mining and the removable of the loosened ore heap shall bepossible to be carried through simultaneously and in independentoperation.

3. Exploration drilling which is conventionally very expensive and cantake a time period of a total of 6-7 years, shall be limited only toconcern mainly determination of principally the approximate limits andextensions of the ore body. Instead the mining equipment shall be sodesigned and adapted that it enables that the ore body is followedmainly independently of its mainly unknown variation with respect tothickness, inclinations, windings and possible faults.

According to one aspect of the invention a method is used, thatresembles the above described mechanized shrinkage stopping techniqueand thereby provides the advantages connected therewith. It should,however, be emphasized that said technique is based upon use ofequipment that requires great space and shall be able to be driven onone and the same continuous guide system in the roof of the rock chamberand the raise. This known technique and equipment are completelyunuseable when it is the question of narrow ore bodies with a width of 4meters at most, the planes of which lean by an angle of an order ofmagnitude of 60°-70° to the horizontal, and which normally have manywindings and possibly faults along their extensions.

By using, according to the invention, in the raise following theinclination of the ore body, a transport lift designed for receiving theworking platform or mining rig in the lift cage, adaption of the size ofthe working platform or mining rig, intended to be suspended on guidesin the roof of the rock chamber, to strongly changing conditions withrespect to shape and dimensions in the ore body is made possible. Thus,in one case it may e.g. be necessary to carry through mining from aworking platform having a width of one meter, form which drilling iscarried through by maens of manual drilling tools, and which is manuallydriven forwardly along the guide. In another case it may be possible touse a broader mining rig with one or more drill booms, and which uses anair motor or electric motor for the propulsion thereof along the guide.

By arranging a guide supsension in the transport lift cage for theworking platform or mining rig, this guide then being sidewardly andlengthwardly movable and connectable to a start guide in the roof on therock chamber, a flexible transistion is obtained for moving the workingplatform or mining rig between the raise and the mining chamber. One andthe same guide suspension can then be adapted for working platforms ormining rigs of different kinds.

At start of the mining the start guide is first provided in the miningchamber roof close to the raise. Preferably, the start guide has ablocking device for the working platform or mining rig suspendedthereon, which automatically starts to operate if the platform or rigshould come in on it, when the transport cage has not yet been moveddown.

Furthermore, preferably air and water feeding lines are connected viathe start guide to air and water conduits for the mining equipmentextending in a conventional way in the guide sections.

The guide sections are provided in the roof of the mining chamber sothat they essentially follow the windings of the ore body and bridge anyfaults, in order to bring the shape of the mining chamber to followessentially the shap of the narrow ore body. For this purpose a set ofshort, angled joining members are included in the mining equipment andarranged to be provided between two guide sections in order to changetheir mutual angle sidewardly and/or heightwardly and/or shift them inparallel sidewardly when the shape and the ore body requires. Forsimilar reasons the mining platform is preferably pivotally suspended onthe guide.

To advantage the invention is used for mining in a chamber extending inthe plane of the ore body and conforming to the shape thereof, andhaving a length of an order of magnitude of 50-200 meters and a heightof 50 meters or more.

Further features, objects and advantages of the invention will appearfrom the following description with reference to the drawings of someembodiments.

On the drawings:

FIG. 1 is a horizontal section through part of the extension of a narrowore body,

FIGS. 2 and 3 are vertical sections along a part of the extension of theore body in the height direction and in the directions of arrows II--IIand III--III, respectively, in FIG. 1,

FIGS. 4-6 schematically, in sections along the plane of the ore body,illustrate three successive preparatory working steps at mining with themethod according to the invention,

FIG. 7 is a horizontal section in the direction of arrows VII--VII inFIG. 6,

FIG. 8 in the form of view along the same plane as FIGS. 4-6 illustratesthe starting step at mining according to a first embodiment of themethod according to the invention, whereby

FIG. 8a in a part view shows the next step,

FIGS. 9-11 in similar sectional views as FIGS. 4-6 illustrate successivefurther operational steps in this first embodiment,

FIGS. 12-14 in similar sectional views as earlier illustrate successiveoperational steps in a second embodiment of the method according to theinvention,

FIG. 15 in a similar sectional view as earlier schematically illustratesa third embodiment of the mining method according to the invention,

FIG. 16 in a similar sectional view as earlier illustrates the principleof venting the mining chamber in the method according to the invention,

FIG. 17 in an amplified schematical sectional view along the same planeas earlier schematically illustrates the principle for suspending amining platform used with the method according to the invention in atransport lift cage extending in a raise,

FIG. 18 in a similar way as FIG. 17 shows the mining platform suspendedon guides in the roof of the mining chamber,

FIGS. 19-21 in schematic part views illustrates the principle forpivotal attachment of guides and mining platform, respectively, in themethod according to the invention, whereby FIG. 21 is a view in thedirection of arrows XXI in FIG. 20,

FIGS. 22a-d in schematic part views illustrate the use of joiningelements between the guide sections.

In the different drawing Figures the same or similarly acting detailshave been provided with the same reference numerals.

FIGS 1-3 illustrate the extension and approximate appearance of a thinore body 1. As appears the ore body can also contain interferringportions 2 of another mineral than the ore intended for mining. Fromtransverse drifts leading to two main level drifts 3 and 4,respectively, two horizontal drifts 6 and 8, respectively, extendingessentially in parallel with respect to each other, are driven in theore body. At presence of said interfering portions it can also besuitable to drive further horizontal drifts 6' and 8', respectively.

From the lower drift 8 two raises 10 and 12, respectively, are driven inthe ore body up to the upper drift 6. This step is illustrated in FIG.4, where the work can be carried out with a conventional guide suspendedraise lift 14.

In parallel with and above the lower drift 8 a horizontal so called conedrift 16 is dirven, the floor of which forms the lower wall of the rockchamber intended for mining. From the drift 8 a number of upwardlywidening loading openings 18 are dirven to the cone drift 16. Althoughthe drift 8 in the example shown is illustrated as extending in the orebody in the form of a so called transport dirft, it is usually preferredto locate the transport drift, then corresponding to the main level 4,sidewardly shifted with respect to the loading openings 18, with socalled holding drifts leading into these. Such holding drifts areindicated by means of dashed lines at 19.

The provision of transport drift 8, cone dirft 16, loading openings 18and holding drifts, if any, can be carried through in a way conventionalin connection with shrinkage stoping.

Referring to FIG. 7 there is installed in the raise 10 a normally toothor pin rack carried transport lift cage 20 filling up the rectangulardrift section as much as possible. This transport lift cage can also becable carried such as is indicated at 21 in some of the followingFigures. The hanging side 22 of the drift section can extend outside theore 24 and the guide 26 for the lift cage 20 is provided on this side.

Referring to FIG. 17, the lift cage 20 in the roof thereof carries aguide 28 for suspension of a mining unit, in the form of a workingplatform or mining rig 30 in the lift cage. The guide 28 is of the sametype and profile as the guide sections intended to be used in the roofof the mining chamber in accordance with the following description. Theguide 28, in a way not shown in detail, is mounted movable sidewardlyand in its length direction in the roof of the lift cage. The miningunit 30 in one embodiment can be essentially only a working platform fordrilling with manually operated smaller drill machines. This embodimentis particularly intended for very small thicknesses, down toapproximately 1 meter, of the ore body. In another embodiment, intendedfor greater thicknesses of the ore body, a greater mining rig can haveone or more drill booms 32 for mechanized drilling, indicated in FIGS.9-15.

In a first embodiment of the method according to the inventionillustrated in FIGS. 8-11, the mining is started, particularly referringto FIG. 8, with horizontal drilling from the working platform or miningrig located in the lift cage 20. After loading and blasting, during thelatter of which the hoist cage 20 is driven upwardly into safety in thedrift 10, a recess 34 is formed in the transition between the raise 10and the roof of the mining chamber, with a length admitting installationof a first guide 36, here called start guide. After installation of thisstart guide 36 in the roof of the recess 34, the guide 28 movablymounted in the lift cage 20 is brought into line with this start guide36 so that the working platform or mining rig can be moved out onto thethe start guide according to FIG. 8a. Referring to FIG. 9, continuedhorizontal drilling is thereafter carried through with loading andblasting and stepwise lengthening with new guide sections 38, up to theraise 12.

In a second step vertical drilling is thereafter started from the raise12 according to FIG. 10 with successive loading of the drill holes,demounting of the guide sections, and blasting, see FIG. 11. The newlyblasted roof does not need to be scaled.

At smaller distances between blasting location and the drift 10 theworking platform or mining rig can be moved, before each blasting, intothe lift cage 20, which is driven upwardly in the raise 10. At greaterdistances it is enough if only the personnel is brought along upwardlyin the raise 10.

After finishing of the vertical drilling mining step, the horizontaldrilling discussed with respect to FIGS. 8 and 9 is started anew.

According to a second embodiment of the method according to theinvention, and referring to FIGS 12-14 the horizontal drilling step iscancelled. Beginning from the lift cage 20, guide sections 38 are,instead, first mounted directly in the available roof of the miningchamber up to the raise 12, see FIG. 12. Thereupon vertical drilling isstarted from the auxiliary drift 12, see FIG. 13. Finally loading,successive disassembling of the guide sections and blasting is carriedthrough in the same way as in the first embodiment see FIG. 14.

The second embodiment of the method according to the invention justdescribed is well suitable for automation using drilling and loadingrobots.

FIG. 15 illustrates a modification of either one of the two describedmethods, that implies that the raise 10 is provided essentiallycentrally in the ore body 24 and a vent drift 40 and 42, respectively,is provided at each end of the ore body to be mined. Thereafter miningis carried through towards both directions from the lift cage 20 witheither one of the two described methods.

FIG. 16 illustrates a very advantageous embodiment of the ventilation ofthe working site. In the drift 6 above the ore body 24 a closure 44 isprovided so that fan driven vent air 45 is thus forced to flow past theworksite via the raise 10 and thereafter upwardly along the auxiliaryraise 12.

In FIG. 18 some further details of a working platform 30 are shown. Moreparticularly, the platform 30 carries on its underside a rollersuspended lower lengthening deck 46, that can be brought to theprotruded position shown and from a platform for scaling and attachmentof new guide sections 38. At 47 support struts are indicated.

With reference to FIG. 19 there are means 48 for suspending at need, theguide sections 38 pivotally in their attachments 50. The pivotedsuspension of the guides eliminates the need of a mounting surfaceextending esentially in the same horizontal plane along the ore body andadmits attachment, e.g. in a hanging wall 52, instead of the roof of thenarrow mining chamber, if this should be regarded as necessary, e.g. ofstrength reasons. Of course, the hanging wall can then also lean towardsa direction opposite to that shown in FIG. 19.

With reference to FIGS. 20 and 21 the mining platform can be pivotallysuspended both about a vertical pivot 54 and a horizontal pivot 56. Inthese FIGS. 58 designates support or drive wheels for the platform onthe guides 38, and 60 is a suspension strut for the platform, see alsoFIG. 18. In FIGS. 20 and 21 and the guide 38 is rigidly attached withits attachment 50 in the horizontal roof of the mining chamber, contraryto the embodiment in FIG. 19. By the pivoted suspension of the miningplatform, it can be flexibly adapted to the changes of direction of themining chamber.

To enable adaption of the extension of the guide sections 38 to thesideward windings of the mining chamber and even bridge smaller faults,joining members 62 of the kind schematically illustrated in FIG. 22 canbe used in arbitrary combinations for angling or shifting in parallel ofthe guide sections 38 with respect to each other. The width of suchjoining section 62 corresponds to the tooth or pin rack pitch of theguide sections, indicated by points 63 in such a way that said pitch isalso maintained in the joint transitions. In order to eliminate risk ofjamming for the pinions cooperating with the tooth or pin rack, thetooth or pin of the joining section 62 that extends in the drawing planein FIG. 22a-c, should be bevelled, i.e. have clearances towards theends.

In order to be able to pass a portion with non-interesting minerals, see2 in FIG. 1, it can be desirable in certain cases to pass it on itsupper or lower side. For this purpose it may be needed to change thedirection of the guide sections upwardly and/or downwardly. Also herejoining elements of a similar type as the joining elements 62 in FIG.22a-care then used. Introduction of such joining elements 64 isschematically illustrated in FIG. 22d.

Since the teeth or pins of these joining elements 64 extendperpendicularly to the drawing plane in FIG. 22d there is no risk forjamming and accordingly there are neither any end clearances required.

Of the above types of joining elements 62 and 64, respectively, twotypes each are required, viz. for the joining elements 62 rightwardlyand leftwardly directed design, respectively, and for the joiningelements 64 upwardly and downwardly directed designs, respectively. Thereason for this is that these joining elements as well the guidesections 38 shall include conduit sections for air and water to themining equipment.

If not otherwise state, the components included in the mining equipment,which have not been described in more detail, can be of conventionalkind. Thus, guide sections, drive means for the transport lift cage,drill rigs, etcetera, be of a conventional design, well known to the manof the art.

I claim:
 1. A method for mining a narrow ore body in a mine having amining chamber comprising the steps of:forming a raise whichsubstantially follows the narrow ore body and is in communication withthe chamber; providing a lift cage movable along the raise, the cageincluding a guide and mining equipment movably attached to the guidefrom which mining operations within the chamber can be carried out;suspending a plurality of guide rail sections from a roof of the chamberso that the guide of the cage can be aligned with the guide railsections suspended from the chamber roof by appropriately positioningthe cage in the raise to permit movement of the mining equipment fromthe guide to the guide rail sections; and moving the mining equipmentalong the guide and the guide rail sections; whereby ore can be minedwith the working equipment as the equipment is moved along the chamberroof.
 2. A method according to claim 1 including the steps of suspendinga start guide from the chamber roof immediately adjacent the raise sothat the mining equipment moves from the guide to the start guide, andpreventing movement of the working equipment from the start guide to theguide when they are not in alignment.
 3. A method according to claim 2including the steps of providing the guide rail sections and the startguide with first conduits for flowing air and with second conduits forflowing water, fluidly connecting the first and second conduits, andflowing air and water through the first and second conduits,respectively, for use in the mining operation.
 4. A method according toclaim 1 wherein the step of suspending the guide rail sections comprisesthe steps of arranging the height and lateral extent of the guide railsections so that they generally follow the contour of the ore body to bemined and bridge any faults that may be present.
 5. A method accordingto claim 1 wherein the raise is at one end of the chamber; and includingthe step of forming auxiliary raise at another, opposite end of thechamber which generally follows the inclination of the ore body at theother chamber end.
 6. A method according to claim 1 wherein the raise isintermediate ends of the chamber, and including the step of formingfirst and second auxiliary raises at respective ends of the chamber. 7.Apparatus for mining a narrow ore body in a mine having a mining chamberand a raise in communication with the chamber, the apparatuscomprising:a lift cage mounted within the raise for movement along theraise, the lift cage including a guide and mine working equipmentsuspended from and movable along the guide; a plurality of guide railsections suspended from a roof of the chamber so that the guide of thecage can be aligned with the guide rail sections by appropriatelypositioning the cage in the raise; and means for connecting the guide tothe guide rail sections when they are in mutual alignment to permitmovement of the cage along the guide and the guide rail sections,whereby ore can be mined with the working equipment as the cage and theequipment are moved along the chamber roof.
 8. An apparatus according toclaim 7 wherein the lift cage further comprises a means for adjustingthe transport guide in transverse and longitudinal directions.
 9. Anapparatus according to claim 7 further comprising a means for pivotallysuspending the mining equipment from the guide rail sections.
 10. Anapparatus according to claim 7 further comprising a means for pivotallysuspending at least on of the guide rail sections from the roof of themining chamber.
 11. An apparatus according to claim 7 wherein theworking apparatus comprises a working deck, the working deck beingshiftable between a drawn and protruding position.
 12. An apparatusaccording to claim 7 wherein the guide rail sections include a startguide located immediately adjacent the raise and means for preventingthe mining equipment from moving past the start guide toward the raisewhen the start guide and the guide are not in mutual alignment.
 13. Anapparatus according to claim 12 wherein the guide rail sections andstart guide comprise air conduits and water conduits, and wherein thestart guide further comprises means for connecting the air conduits andwater conduits, respectively, for use in the mining operation.
 14. Anapparatus according to claim 7 further comprising relatively shortjoining members which are non-parallel to the guide rail sections forjoining guide rail sections such that the guide rail sections followirregular portions of the ore body.